Working vehicle

Abstract

A steering apparatus for a working vehicle is provided which is capable of steering dirigible wheels by increased steering angles while checking sideways sliding of the wheels on the ground. For this purpose, a pair of right and left intermediate cases are supported by right and left wheel supports of a vehicle body, each to be pivotable about a first steering axis extending substantially vertically. Each intermediate case supports an axle case in a position thereof opposed to the associated dirigible wheel, to be pivotable about a second steering axis extending substantially vertically. The axle case supports the associated dirigible wheel to be rotatable on an axle.

What is claimed is:  
     
       1. A working vehicle comprising: 
       a vehicle body;  
       a pair of right and left dirigible wheels each having an axle;  
       a steering wheel for steering said pair of right and left dirigible wheels;  
       a pair of wheel supports arranged in right and left positions of said vehicle body;  
       intermediate cases each supported by one of said wheel supports to be pivotable relative to said one of said wheel supports about a first steering axis extending substantially vertically;  
       axle cases each attached to a side of one of said intermediate cases opposed to one of said dirigible wheels for supporting said one of said dirigible wheels on one of said axles, each of said axle cases being pivotable relative to one of said intermediate cases about a second steering axis extending substantially vertically; and  
       a steering control mechanism operable in response to turning of said steering wheel for swinging each of said intermediate cases about said first steering axis and swinging each of said axle cases about said second steering axis, thereby steering said pair of dirigible wheels relative to said vehicle body.  
     
     
       2. A working vehicle as defined in  claim 1 , wherein, when said right and left dirigible wheels are in a straight moving state, said second steering axis is displaced from said first steering axis longitudinally of said vehicle body. 
     
     
       3. A working vehicle as defined in  claim 1 , wherein said steering control mechanism includes a control mechanism for linking one of said axle case and said intermediate case to said steering wheel, and an interlock mechanism for interlocking the other of said axle case and said intermediate case to said control mechanism. 
     
     
       4. A working vehicle as defined in  claim 3 , wherein said interlock mechanism includes a pivot link extending from the other of said axle case and said intermediate case to said wheel support. 
     
     
       5. A working vehicle as defined in  claim 1 , wherein: 
       said first steering axis and said second steering axis extend parallel to each other, said dirigible wheels being drive wheels; and  
       a transmission system for transmitting drive from said vehicle body to each of said dirigible wheels includes a gear transmission having a first spur gear rotatable about said first steering axis and a second spur gear rotatable about said second steering axis.  
     
     
       6. A working vehicle as defined in  claim 5 , wherein said gear transmission is mounted in said intermediate case, and has a first transmission shaft rotatable about said first steering axis and interlocked at a lower end thereof to a second transmission shaft rotatable about said second steering axis. 
     
     
       7. A working vehicle as defined in  claim 6 , wherein said axle has a large diameter spur gear mounted to be rotatable therewith, said large diameter spur gear being interlocked to an intermediate transmission shaft through a small diameter spur gear, said intermediate transmission shaft being interlocked to said second transmission shaft through a pair of bevel gears, whereby said axle is interlocked to said second transmission shaft with a decelerating effect.